“Spec Check”: How to Ensure Compliant Specifications

Optimal Low-E Coating Placement for Double- and Triple-Glazed IGUs

Achieving optimal performance of solar control low-e glass and passive low-e glass requires proper placement of low-e coatings on the glass surfaces of an insulating glass unit (IGU). Placement considerations vary depending on whether the glass is solar control low-e glass or passive low-e glass, and whether the IGU is double- or triple-glazed.

For double-glazed IGUs using solar control low-e glass, orient the coating on the inside of the outward most (building exterior) lite—the second surface—of the IGU. The addition of argon gas or a second low-e coating on the 4th surface will further improve performance.

For triple-glazed IGUs using solar control low-e glass, orient the low-e coating on the second and fourth surfaces of the IGU. Here, the addition of argon gas or a third low-e coating on the 6th surface will improve performance slightly.

For double-glazed IGUs with passive low-e glass, orient the coatings on the surfaces of the inward most (building interior) lite of glass. Similar to solar control low-e glass, the addition of argon gas or a second low-e coating on the 4th surface will improve performance.

For triple-glazed IGUs with passive low-e glass, Orient the passive low-e coating on one of the surfaces on the inward most lites of glass. To improve performance slightly, add argon gas or a third low-e coating on the 6th surface.

In the grand scheme of things, how does fabricated glass impact the overall installed curtain wall costs of a project? PPG has developed this guide to help you make more informed decisions in the evaluation, selection and specification of architectural glass products.

How to Read Color In Glass

How does the commercial building industry ensure precise color accuracy in glass coatings? This article walks you through key color measurement systems and ASTM standards while providing recommendations on evaluating architectural glass samples for color accuracy.

Heat-Treated and Spandrel Glass

INSLIP and INSLOP

Placement of a laminated lite within an insulating glass unit (IGU) is key to how its glazing system will perform. INSLIP and INSLOP are two commonly used terms to help designers position laminated glass properly.

Bent & Laminated Glass

Bird-Friendly Glass

Each year, more than 600 million birds die from collisions with glass in the United States alone. Although bird-friendly building regulations continue to increase in North America, glazing options have been limited.

Low-E Demonstration

Spandrel Glass

Unlike vision glass, which is meant to be transparent, spandrel glass is designed to be opaque in order to help hide features between the floors of a building, including vents, wires, slab ends and mechanical equipment.

Tdw-ISO: Fading Factors

For years, UV light transmittance used to be thought of as the measure of a glazing material's ability to protect furnishings from fading due to sunlight exposure. Now, ISO Damage Weighted Transmittance, or Tdw-ISO, is considered the most accurate criterion for assessing potential fading damage.

Types of Glass Fabrication

Glass fabrication is an important part of glass specification. There are several basic types of fabricated glass, which all offer unique pros and cons. Types of glass fabrication include insulating glass units, laminated glass, opacified glass, decorative glass and more.

Short Wave and Long Wave Energy

Understanding the solar energy spectrum is key to understanding glass coatings. Glass coatings affect the way the different parts of the solar spectrum are absorbed into, transmitted through or reflected off of glass, all of which factor into the glass' energy efficiency.

Heat-Treated Glass: It's All About the Pressure

When designing with large expanses of glass, it is critical to know when the glass may need to be heat-treated for durability and/or safety. The type of processing required—heat strengthening or tempering—depends on the specific application.

Designing Glass to Resist Wind and Snow Loads

The impact of wind and snow on a building can be significant, which is why accommodating for wind and snow loads is an important upfront consideration during the design and specification phase. It is a multi-step process, with ASTM E1300 serving as the main source of technical information to determine the right glass thickness and type to meet a project's anticipated demands.

Condensation: What it is. What it means.

Determining the Right Glass for the Right Acoustics

While glass looks great aesthetically, it also has to meet high performance standards. And an important part of performance relates to acoustics—whether it's large, dramatic panels used for the exterior of a building, or smaller panels used to create interior partitions.

Spontaneous Breakage of Glass

Sometimes glass breaks in a building without any obvious cause. When this occurs, it could be due to glass edge damage or surface damage from handling and glazing that then weakens the glass during high winds, building or framing system movement, vandalism, or a specific type of inclusion inside the glass.

How Glass is Made – From the Batch House to the Lehr

Glass has become one of the most popular building materials used today because it offers virtually unlimited aesthetic options, combined with outstanding performance. What ends up as large, sweeping glass panels in a high-rise office building, healthcare facility, school, or other construction project starts as a simple combination of sand, gympsum, soda ash, limestone and dolomite.

What Glass Does with Solar Energy

There are three parts to the solar energy spectrum: infrared, visible and ultraviolet. Glass consequently responds to these three different types of light in three different ways: by reflecting, absorbing or transmitting it. Tints and coatings can be used to impact that response in order to improve overall glass performance.

North American Glass Channel

The North American Glass Channel chart demonstrates the many different processes involved in the production of commercial glass and the capabilities of the largest channel participants from primary glass manufacturers and low-e coating manufacturers, to glass fabricators and glazing contractors.

How Low-E Glass Works

Technological advances continue to improve the solar and thermal performance of glass. One way this performance is achieved is through the use of passive and solar control low-e coatings, which minimize the amount of ultraviolet and infrared light that is able to pass through the glass without negatively impacting the amount of visible light that is transmitted.

Solar Energy Spectrum

Heat Strengthened vs. Tempered Glass

Sweeping expanses of glass create an amazing visual impression, as well as provide a pleasant environment with vast amounts of natural light. Prior to installation, the glass may need to be heat-treated for durability and safety reasons. The type of processing required – heat strengthening or tempering – depends on the glass' specific application.

Low-E Coatings Thickness

Preventing Thermal Stress Breakage

It's beautiful and durable, but working with glass does come with some special considerations. This is especially true in commercial architecture, where it's common to specify large glass panels to achieve a dramatic look. A thermal stress break is one such issue.

Specifying Large Insulated Glass Units

When thinking of some of the world's most dramatic, visually breathtaking buildings, they most likely involve large expanses of glass. Using large, dramatic panels of insulated glass is one of today's most popular design trends. Aesthetically, glass looks good. It's also economical and energy efficient. Not to mention, it's been proven that the natural daylight glass lets in just makes people feel better.

Top Design Considerations

Specifiers and design professionals often select glass for projects based on its stunning aesthetics and energy-efficient performance. However, designing with glass requires special considerations – especially during the selection and specification process.

“Float” describes the process by which nearly all commercial “flat” glass is made, so “float” glass and “flat” glass are really the same thing.

Tempered glass is four times stronger than regular glass; heat strengthened is just two times stronger.

Pure glass is incredibly strong – it only scratches or breaks because of imperfections that can occur during the manufacturing process.

The first insulating glass units were developed in 1945 for the Pullman Car Company in Butler, PA.

If you see condensation on the outside of your low-e glass windows, it means the coating is working properly.

The word window comes from a Norse term translated "wind eye", for "eye on the weather."

A standard float tank can produce glass 24 hours/7 days a week for up to 15 years before it needs to be rebuilt.

Tempered glass deflects just as much as annealed glass. It also weighs the same.

Insulated Glass Units are made with two or more lites of glass with a hermetically sealed space filled with dry air or insulating gas.

Insulated glass units or double glazed units are a significantly more energy efficient glazing system than single glazing.

IGUs reduce the likelihood of interior condensation forming by providing a thermal barrier between the inside and the outside. The thermal barrier makes interior spaces more comfortable as it is easier to maintain a consistent indoor environment.

Thermal or insulation improvements achieved with an IGU work day and night in both summer and winter conditions, reducing heat entry and heat loss.

IGUs reduce sound transmission and provide quieter interior spaces.

Clear glass isn’t actually clear. It has a light green tint, which can be seen when held against a white background.

Due to the chemistry involved in the float glass process, all the colors of the rainbow are not possible. For example, orange, red, yellow and violet colored glasses cannot be produced using standard float technology.

How much does glass weigh?

Glass 6mm thick will weigh 2.9 lbs. per square foot.

Glass Education Center

The single source for information on designing, specifying and building with commercial glass.